CVE-2026-64073: Linux kernel · irq_work: Fix use-after-free in irq_work_single() on PREEMPT_RT
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 7.8 High · fixed in 6.8.0-1064.67~22.04.1 : patch Linux kernel soon.
Data as of 26 Oct 2026, 17:16 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 2% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 6.8.0-1064.67~22.04.1, 6.8.0-1067.75~22.04.1, 6.8.0-1065.72~22.04.1 +41
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 19 Jul 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Upgrade to a fixed release listed under Affected software.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 26.04 LTSlinuxpkg:deb/ubuntu/linux?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-azure-fdepkg:deb/ubuntu/linux-azure-fde?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-gcppkg:deb/ubuntu/linux-gcp?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-gkepkg:deb/ubuntu/linux-gke?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
An official patch is available and should be applied to affected Linux kernel versions. The vendor advisory confirms that this issue has been fixed. Systems running affected versions should be updated promptly to incorporate the fix that wraps irq_work execution in RCU critical sections and synchronizes RCU grace periods to prevent use-after-free.
Description
A use-after-free vulnerability in the Linux kernel's irq_work subsystem on PREEMPT_RT was fixed. The flaw occurs because irq_work_single() dereferences a work pointer after clearing a BUSY flag, while another CPU might free the work prematurely, leading to use-after-free. The fix involves wrapping the execution in an RCU read-side critical section and synchronizing RCU grace periods to prevent premature freeing.
References
- ubuntu.com/security/CVE-2026-64073 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-64073 (opens in a new tab)
- git.kernel.org/linus/91840be8f710370607f949a627e070896faeddb8 (opens in a new tab)
- ubuntu.com/security/notices/USN-8593-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8603-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8618-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8663-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8664-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8728-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8729-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8761-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8729-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8761-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8781-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8729-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-8761-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-8802-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8728-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8729-4 (opens in a new tab)
- ubuntu.com/security/notices/USN-8729-5 (opens in a new tab)